TEST: Does running make you smarter? If you answered yes, read on: If no, you should go run.

1. Running helps your brain grow. Don't worry — we're not talking bursting-through-your-skull growth. Running stimulates the creation of new nerve cells and blood vessels within the brain, an organ that tends to shrink as a person ages. Also, studies have shown that running may help increase the volume of the midbrain (which controls vision and hearing) and the hippocampus (which is linked to memory and learning). 2. Running helps your brain age better. In addition to preventing or reversing age-related shrinkage, running affects brain chemicals in a way that sets runners up to have healthier-than-average brains later in life. A study last year measured neural markers and cognitive function in middle-aged athletes and non-athletes, and while the cognitive function scores were the same, researchers found the athletes' brains showed greater metabolic efficiency and neural pl...